Final answer:
Tiberius adopted Germanicus, who was later suspected of being poisoned in 19 AD during his service in Syria under suspicious circumstances. Tiberius is portrayed negatively by historical sources, and he was succeeded by his grandnephew and adopted son, Gaius (Caligula).
Step-by-step explanation:
Tiberius adopted Germanicus, but it is later believed that Germanicus was poisoned in 19 AD. The adoption took place in 4 CE, and Germanicus was well-regarded as a military commander, having led campaigns in Germany and later being stationed in Syria. While in Syria, Germanicus had conflicts with the governor, Gnaeus Piso, and it was after his transfer here that he fell ill and suspicions of poisoning arose. Tiberius, who became emperor after the death of Augustus, had a generally negative representation in historical sources, with Tacitus depicting him as paranoid and Suetonius seeing him unfavorably compared to Germanicus. Despite such views, Tiberius's reign allowed for a relatively smooth transition of power to his grandnephew and adopted son Gaius (Caligula), who succeeded him after his death. This turbulent period of Roman history is marked by political intrigue, familial relationships, and the precarious nature of succession in the Roman Empire.